Those film lenses may have been competitive at the time but that was over 20 years ago. Optical design has moved on a great deal since then. Then there is the impact of lead removal legislation which means new designs are needed. Screw drive AF just isn't going to be acceptable for flagship class lenses so a state of the art in-lens motor system will be needed.

Slapping a fresh coating on 20 year old lenses will get Pentax laughed off the pitch. Pentax isn't competing with its own history but with the current market.